Category: Education and Science Kits Product Review: National Geographic Starter Rock Tumbler Kit-Includes Rough Gemstones, 4 Polishing Grits, Jewelry Fastenings & Detailed Learning Guide - Great STEM Science Kit For Mineralogy & Geology Enthusiasts The National Geographic Starter Rock Tumbler Kit is an excellent educational and science kit for anyone interested in mineralogy and geology. The kit includes rough gemstones, 4 polishing grits, jewelry fastenings, and a detailed learning guide that provides information on the different types of rocks and gems found in the tumbler. One of the great things about this kit is its ability to turn rough rocks into beautiful gems through the process of polishing. The four polishing grits included in the kit allow for easy and effective polishing, resulting in a smooth and shiny finish. Additionally, the jewelry fastenings provided in the kit can be used to create unique pieces of jewelry from the polished gemstones. The detailed learning guide that comes with the kit is also very helpful. It provides information on the different types of rocks and gems found in the tumbler, as well as how they are formed and what makes them valuable. This information can be used to enhance the educational experience for students or simply to satisfy one's curiosity about mineralogy and geology. Overall, the National Geographic Starter Rock Tumbler Kit is an excellent choice for anyone looking to learn more about mineralogy and geology while also having fun.